Point Defects and Diffusion

Abstract

Diffusion in solids occurs as a result of a large number of thermally activated atomic jumps from one lattice position to another. When two atoms simply exchange positions large distortions of the crystal are required to allow the atoms to squeeze past each other and the rate of this process is much too small to account for the experimentally observed diffusion rates. In practice the atomic movements involve the cooperation of point defects in the crystal and the diffusion coefficient can be related to the concentration and migration of these defects. Thus diffusion data represents a source of information on these basic point defect properties.